This application is related in general to multi-processor computer systems, and in specific to an arrangement for packaging architecture for multi-processor computer systems.
In prior art systems 100, a midplane 101 is used as the backbone for component interconnect, as shown in FIG. 1. A plurality of processor boards 102, memory boards 103, and I/O boards 104 are coupled to the midplane 101. Controller chips 105 handle transporting transactions between the different components. Controller chip 106 manages transactions between system 100 and another system.
This arrangement has several disadvantages. One is the long length the data must traverse in moving between the processor and memory, processor and processor, and between the processor and I/O. For example, for a memory transaction, data must flow from the processor board 102 to the midplane 101, through a series of controller chips 105, and then to the memory board 103. Responses flow back through this path to the processor. The long paths slow the computer system, and are an inefficient use of resources.
The dispersed and shared nature of the various components, 102, 103, 104, does not allow for hot swapping of components. Thus, if one component has malfunctioned, for example a processor board 102, then the entire system must be shut down so that the faulty component can be repaired and/or replaced. Thus, the prior art systems could not meet high availability requirements due to lack of supporting hardware and firmware.
These and other objects, features and technical advantages are achieved by a system and method which uses a backplane to interconnect a plurality of modular cell boards. The cell board is the building block of the computer system. Each board comprises a plurality of processors, a processor controller subsystem, and a memory subsystem. For example, each board could comprise 4 processors, 1 processor controller chip, and 32 memory DIMMs. The processor controller chip manages communications between components on the cell board. The cell board also comprises a power subsystem, which may be located on a cell board or an a separate board that is connected to the cell board. A mechanical subassembly provides support for the cell board, as well as ventilation passages for cooling.
The controller chips, namely the crossbar chips and the router chips, are connected to one side of the backplane, while the cell boards are connected to the other side. The crossbars chips manage cell board to cell board communications. The router chips manage communications between computer systems located in different cabinets, e.g. the router chips manage communications between backplanes. For example, each backplane could comprise connections for 8 cell boards, 4 crossbar chips, 2 router chips, and three backplane power boards. Note that the power boards enable N+1 power supplying, such that the system would require N power supplies (for example, 2), and the +1 is a redundant power supply that allows for hot swapping power supplies, e.g. in field servicing and replacement. The controller chips are located adjacent to the power boards, such that air cooling is used for the controller chips and the power boards.
The cell boards are arranged in back to back pairs, with the outer most cell boards having their components extend beyond the height of the backplane. This allows for an increase of spacing between the front to front interface of adjacent cell boards. Thus, the backplane board area can be less than the area required to cover the arrangement of cell boards. In other words the footprint of the cell board connectors is smaller than the footprint of the cell board components.
The arrangement of the memory on the cell board reduces the path length, as well as handling chips required, for processor to memory transactions. This results in an increase in system speed.
The interconnection of the components via the backplane uses less physical space, and a reduction in interconnection cables and repeater chips.
The modular arrangement of the components allows for hot swapping (on-line field repair/replacement) of cell boards, power board, and controller chips (on backplane).
The arrangement of components also allows for forced air cooling. The component that require cooling are arranged such that air may be forced in one direction through the cabinet, and thus cool all of the components. This is less hazardous and less expensive than liquid cooling or freon based cooling.
The inventive arrangement has a reliable, hot swappable power system that has optimized distribution paths.
The system uses standard PCB board sizes while allowing the connection of processors that are wider than the boards.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.